Endovascular repair of an abdominal aortic aneurysm (AAA) is commonly performed using stent or graft (stent-graft) prostheses. Stent-graft prostheses can perform much like surgical grafts by bridging the dilated segment of an aneurysm, thereby, excluding it from direct blood flow. The purpose of stent-graft prostheses is to protect the excluded aneurysm from arterial pressure, dilatation, and rupture, while maintaining blood flow downstream. If any type of leakage occurs either at the site of interaction between the stent-graft and the bodily tissue, between any two components of the stent-graft, or through small perforations in the stent-graft, then the purpose of the stent-graft is defeated resulting in a continuation of the risk associated with rupturing. Although a stent-graft may be initially secured in place through the use of frictional forces or fixation barbs, migration of the stent-graft away from its original position exasperates the possibility of leakage. The only remedy for such an occurrence is early detection and re-intervention, e.g., repair by implanting a new stent-graft.
The treatment for a ureteral obstruction or fistula also commonly involves the use of stent-graft prostheses. The purpose of stent-graft prostheses in such an application is to provide urinary drainage from the renal pelvis of the kidney into the bladder. Similarly, stent-graft prostheses can be used to allow sufficient drainage from the liver through the biliary ducts, from the pancreas through the pancreatic ducts, and from the gall bladder through the bile ducts. Peristaltic action in the ureter often results in the migration and possibly even complete expulsion of the graft-stent from the ureter. In order to prevent migration, many ureteral stent-graft prostheses are provided with a curled extension located at the proximal and/or distal end. Unfortunately, the presence of such a curled end increases patient discomfort and irritation of the bladder or kidney.